How To Install A Hi-Po Manual Choke

Hi-Po manual choke conversion kits from Mustangs Etc.

Jim Smart

April 17, 2014

Confound it the frustrations associated with automatic chokes. They either don't choke enough and the darned thing stalls when it's cold or they choke too much and it is fouled spark plugs and sooty exhaust. If only you had more control of your Mustang's cold start and choke operation. Mustangs Etc. makes that control possible with its 289 High Performance manual choke conversion kit for Autolite 4100 and 2100 carburetors. This conversion kit installs in about one hour and affords you new levels of cold start fuel metering control.

Before you install the Hi-Po manual choke system, you must first remove the automatic choke assembly, which can be done in minutes using a screwdriver and needle nose pliers. Installation of the manual choke control components takes just minutes and when you're done you will have total control of your choke's operation no matter the outside temperature or drive cycle you are in.

01. This is the Autolite 4100 four-barrel carburetor for the ’65-’66 289-4V engine with heat tube style automatic choke, which gets its modulation heat from the hot exhaust manifold. A heat-sensitive bimetallic coil closes the choke plate when the engine is cold. As the engine’s right hand exhaust manifold heats up, manifold heat is drawn via manifold vacuum to the choke coil, which expands and pulls the choke and fast idle cam off during warm-up.

02. The Autolite 2100 two-barrel carburetor is nothing more than a 2V version of the 4100 with primary bores only. The 2100 is equipped with the same automatic choke assembly as the 4100 and can also be converted to manual choke as well.

03. This is the 289 High Performance manual choke kit from Mustangs Etc. for Autolite 2100 and 4100 carburetors equipped with automatic choke. It is unknown at press time whether this new kit will include a cable assembly for in car operation or if you’ll have to source your own.

04. Here’s a typical off-the-shelf Autolite 4100 carburetor with automatic choke. Removal is easy using a common screwdriver and needle nose pliers. The thermostatic coil/cap is removed first with a flat blade screwdriver.

06. A C-clip secures the fast idle cam and linkage. Pop this clip and remove the automatic choke housing.

07. The automatic choke assembly as it stands as a separate bolt-on assembly. These are not reproduced so you may wish to pack this part away with your other original Mustang parts.

08. The Autolite 4100 carburetor void of its automatic choke. We’re going to show you how easy it is to fill this spot with a manual hand-choke conversion from Mustangs Etc.

09. The automatic choke link shown here needs to be removed with a ¼-inch socket because the manual choke link has a spring-loaded choke pull-off.

10. Where this gets tricky is the choke blade and shaft. The shaft link is different from an attachment standpoint and must be swapped, which involves grinding the end of the shaft where it is peened, removing the automatic choke link and securing the manual choke link and peening the shaft end or using an industrial adhesive.

11. This is why the link has to be changed. The lock cam is indexed at 9 and 3 o’clock instead of 12 and 6 o’clock. The manual choke pull-off spring allows some engine breathing with the choke full on.

12. The manual choke link is installed by rotating the choke plate until the lock cam ears can pass through the linkage and secured in place like shown.

13. The automatic choke heat vacuum port in the base of the carburetor is plugged as shown with a threaded brass plug included in the kit.

14. The manual choke cable mounting bracket, which is also where the cable adjustment is made, is installed next onto the carburetor using two of the original choke housing attachment points.

15. The fast idle cam and linkage are installed next and secured with the original C-clip.

16. This is a finished shot of the installation of the manual choke linkage and fast idle cam. All that is left to do is determine the routing and installation of the manual choke push/pull cable inside the car.